# Rectangle Inscribed in Semicircle...Part 2

• Aug 29th 2008, 12:06 PM
magentarita
Rectangle Inscribed in Semicircle...Part 2
A rectangle is inscribed in a semicircle of radius 1.

(a) Find the angle theta that results in the largest area A.

(b) Find the dimensions of this largest rectangle.

P.S. Have a wonderful Labor Day weekend everyone on this math site.(Hi)
• Aug 29th 2008, 02:29 PM
Jhevon
Quote:

Originally Posted by magentarita
A rectangle is inscribed in a semicircle of radius 1.

(a) Find the angle theta that results in the largest area A.

(b) Find the dimensions of this largest rectangle.

P.S. Have a wonderful Labor Day weekend everyone on this math site.(Hi)

see my response to part 1 of this question. also note that the height of the rectangle would be $y = \sqrt{1 - x^2}$ while the base would be $2x$
• Aug 29th 2008, 06:31 PM
magentarita
Are you..
Are you saying that this question has been answered in full?
• Aug 30th 2008, 03:58 AM
skeeter
no, but here are a couple of hints ...

$A = \sin(2\theta)$

what is the largest possible value of sin(anything) ?

at what angle does that largest value occur ?
• Aug 30th 2008, 05:37 AM
magentarita
Sorry...
Quote:

Originally Posted by skeeter
no, but here are a couple of hints ...

$A = \sin(2\theta)$

what is the largest possible value of sin(anything) ?

at what angle does that largest value occur ?

Sorry but I'm still lost.
• Aug 30th 2008, 01:25 PM
skeeter
one more time, with another hint.

this is a fact ... -1 < sin(anything) < 1

what is the largest possible value of $\sin(2\theta)$ ?

what value of $\theta$ will make $\sin(2\theta)$ that maximum value ?
• Aug 31st 2008, 05:24 PM
magentarita
again...
Quote:

Originally Posted by skeeter
one more time, with another hint.

this is a fact ... -1 < sin(anything) < 1

what is the largest possible value of $\sin(2\theta)$ ?

what value of $\theta$ will make $\sin(2\theta)$ that maximum value ?

Try to understand that I am a struggling math student. I am not the most gifted in my class. I am trying to make it through. Your replies are not helping because math and I do not walk hand in hand. Get it?
• Sep 1st 2008, 01:00 AM
Moo
Quote:

Originally Posted by magentarita
Try to understand that I am a struggling math student. I am not the most gifted in my class. I am trying to make it through. Your replies are not helping because math and I do not walk hand in hand. Get it?

Struggling math students who want to succeed make the efforts to understand or to try or to make attempts.

No one here will laugh at you because you don't understand or because your solution is silly. So try to show us what you've understood from the explanations above. It will be easier to spot out what you don't understand and to explain it to you more specifically.
What skeeter wrote in his very last message is understandable by high schoolers, and not only the gifted. So if you think a little, you may be able to figure out what he's trying to tell you ;)

Remember that it's you and only you who will write the exams, you won't have the support you're too generously given here. I'm not saying that we shall not help you, it's just that for some people, you look like you just want the solutions with all the steps, even in similar exercises and this is definitely not useful in some situations.

Edit :
have a look here : http://www.mathhelpforum.com/math-he...772-post3.html
It may be a particular case, but this guy asked his question, I told him what he needed for solving, he tried an answer without being sure (?) and it was the correct answer ! This is the kind of people it is very pleasant to help, because they make the effort to understand and we see it. You may try to understand, but we don't see it. That's kind of a difference...

Plus, you get pleasure of having found the solution by yourself, and maybe in the future you will say "Hey ! This looks like the problem I managed to solve !" rather than "Uh... it looks like what .... solved for me, but ... I don't quite remember what he was saying"
You will remember how you found the solution if you make it yourself, whereas you'll only remember the answer/steps when one gives you full solution.

*uuuh I'd better stop here lol*
• Sep 1st 2008, 03:17 AM
magentarita
Moo
Moo,

I understand what you are saying. I will place my attempts on this site and hopefully you guy will be able to show me the right way from the mess I create.

Thanks,
Rita